A campaign representing around 2,000 British pensioners is set to revive legal action against the Bank of Ireland (BoI) over attempts to confiscate £46m of their bonds.

The Irish finance minister Michael Noonan announced last Wednesday that bondholders had until 5.30pm today to respond to a plan that would see the bonds wiped out as part of a €4.2bn (£3.6bn) capital-raising for the bank. The state is a 15 per cent shareholder in BoI and is attempting to shore up the banking system following the country's financial crash.

The pensioners hold permanent interest bearing shares (pibs), which payout 13.375 per cent on face value every year. They were issued by the old Bristol & West building society, which was taken over by the BoI in 1997.

The BoI already withdrew one attempt to take back the shares for as little as 1p for every £1,000 in the summer. This followed the threat of legal action by Albert Kempster, a 73-year-old pensioner who relies on the pibs for financial survival.

The campaign, organised by bond expert Mark Taber, has been in touch with about 500 pensioners and has called on them to complain to Mr Noonan about his plans ahead of today's deadline.

However, if Mr Noonan ignores their pleas and pushes through the cancellation of the pibs, the campaign has again asked lawyer Brown Rudnick to challenge either the government in the Irish courts or sue the BoI in the UK. It is likely they will focus on the terms when the pibs were formally transferred from UK to Irish jurisdiction in 2007, alleging that this was a flawed process.

Mr Taber said: "The focus at the moment is to persuade them not do this, but if the worst happens we will be looking at legal action. Most of the holders of these bonds are very elderly and wouldn't necessarily be aware that this is even going on."

The campaign is critical of Mr Noonan for giving the pensioners just seven days to respond. Mr Taber says many of the pensioners will be in care and would not have access to the London Stock Exchange's Regulatory News Service – the specialist newswire on which it was announced. Other campaigners are to protest outside Post Offices. The BoI signed a deal to provide savings account services to the Post Office in 2004.